Scenario:
Installation of Microsoft Office SharePoint Server 2007 (MOSS 2007) SP2 may activate a product expiration date, meaning that your SharePoint server will stop working 180 days after installation of SP2.
Resolution:
Details are available at following SharePoint Team Blog entry:
http://blogs.msdn.com/sharepoint/archive/2009/06/25/service-pack-2-update.aspx
Hot Fix is available from following URL: